Among other applications, the invention applies to the phosphate mines of Florida in which the ore extracted from mine cuts is separated in a washing plant into 3 components: a concentrated phosphate, a siliceous sand, clay earths (montmorillonites and attapulgites).
Currently, one washing plant delivers 2,000,000 tons of clay per year, contained in 50,000,000 m.sup.3 of clayey water.
The volumes are discharged at considerable rates into reservoirs covering several km.sup.2 where natural decanting takes place. The reservoirs are provided with embankments which rise about 15 m above the original ground level. They are gradually abandoned full of viscous mud at 25% concentration. This solution is undesirable and the public authorities have published new regulations requiring all mined surfaces to be returned to their former state with the same flora and fauna and prohibiting, in particular, said mud reservoirs. These reservoirs also constitute a danger the event of their embankments breaking.
The present invention therefore aims to provide an installation for spreading clayey mud with a view to its subsequent dehydration and solidification on terrain which returns to a useable condition.